Just like photons are particles of light, there are also phonons, which are particles of sound. Photons are called photons and phonons are called phonons. Just as light is an oscillation of electric and magnetic fields and photons are particles with wave energy, sound is motion and phonons are particles with wave energy. Photons are elementary particles and phonons are quasiparticles, but the quantum world may be expressed differently depending on how you perceive it.
Phonons as energy waves
Atoms bond to each other like springs, forming a crystal lattice that constantly vibrates. Sound is transmitted when these vibrations travel like waves through matter. We often think of sound as waves or vibrations, such as the sound of the word “sound wave,” the vibrations that occur when sound is made, or the vibration of the eardrum, so talking about sound as waves is easy to imagine.
Phonons as sound particles
Phonons as particles do not have a physical size, but are expressed as a wave length and energy amount. The wavelength is on the order of nm, the energy is about a few meV, and the charge is neutral. Phonons are like counting the energy of vibration, and at absolute zero, where there is no vibration, there are zero phonons, and as the temperature is raised and the vibration becomes stronger, the number of phonons increases. It’s a strange feeling to perceive sound as particles.
Acoustic and optical phonons
There are two types of phonons: acoustic phonons and optical phonons; acoustic phonons vibrate in the same phase as adjacent phonons, while optical phonons vibrate in the opposite phase. Acoustic phonons are low energy, are similar to the image of sound waves, and transmit heat, while optical phonons are high energy and interact with light. The speed of sound is the speed at which phonons move, and the transmission of heat is the movement of phonons. Sound appears to be closely related to both heat and light.
Heat, resistance, magnetism, and phonons
A strong lattice structure allows phonons to move smoothly, so thermal conductivity is high, and fewer phonons means less heat transfer. Also, when electrons move within a crystal, they are hindered by phonons, which creates electrical resistance, so this seems to be related to resistance. There is also talk that this is related to magnetism.
Phonons is amazing
Phonons transport sound, interact with photons and electrons, transmit heat, and seem to be related to magnetism. When you dig deep into the quantum world of sound, you see how phonons is linked to so many phenomena. Vibration is the key that connects so many phenomena. Phonons is amazing. The many phenomena on Earth are amazing.
